Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Assumptions Used to Calculate Fair Value of Options Granted to Employees

The fair value of stock options granted to employees during the years ended December 31, 2019 and 2018 was estimated at the date of grant using the following assumptions:

	Years Ended December 31,
	2019	2018
Risk-free interest rate	1.6 – 1.8%	2.3 – 2.9%
Expected dividend yield	0%	0%
Expected term	5.3 – 5.4 years	5.3 – 5.8 years
Expected volatility	67%	62 – 64%

Schedule of Recognized Stock-Based Compensation Expense

The Company recognized stock-based compensation expense during the years ended December 31, 2019 and 2018 as follows:

	Years Ended December 31,
(in thousands)	2019		2018
Research and development expense	$	223	$	1,092
General and administrative expense		2,148		1,958
Total stock-based compensation expense	$	2,371	$	3,050

Summary of Stock Option Activity

The following table summarizes stock option activity during the year ended December 31, 2019:

(in thousands, except per share amounts)	Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Outstanding at December 31, 2018		2,233		$	14.97		7.66	$	—
Granted		3,910		$	12.67
Exercised		(37	)	$	3.90
Forfeited		(4,182	)	$	14.32
Outstanding at December 31, 2019		1,924		$	11.93		6.71	$	12
Vested and expected to vest at December 31, 2019		1,924		$	11.93		6.71	$	12
Exercisable at December 31, 2019		1,360		$	14.14		5.97	$	2